Fuel feed and power control device for combustion engines



Sept. 29, 1959 L. ROBINSON 2,906,093

FUEL FEED AND POWER CONTROL DEVICE FOR COMBUSTION ENGINES Filed Feb. 1, 1955 2 Sheets-Sheet 1 /Z L 5 H 0 '0 68 3 32 66 z Z2 FltZ n 4 1 76 70 TTE. l

P 1 L. ROBINSON 2,906,093

FUEL FEED AND POWER CONTROL DEVICE FOR COMBUSTION ENGINES Filed Feb. 1, 1955 2 Sheets-Sheet 2 a /Z6 2 5 ,s I f 2/2 J00 -Z04 236 Q 264 INYENTOR. ([JffJPZ. fog/Mm Figure 5 is a schematic showing of a modification of the apparatus shown in Figure 1.

Referring now to Figure 1, a gas turbine engine is generally indicated at and includes a series of annularly disposed combustion chambers 11 mounted in a casing having a header or air intake section 12, and a compressor 13, shown as of the axial flow type, which is driven by means of a turbine 14 through a shaft 15. Each of the combustion chambers is provided with a burner nozzle 16 to which metered fuel is supplied under pressure by way of a conduit 17, fuel manifold 18 and individual fuel lines 19. The conduit 17 receives metered fuel from a fuel control device, generally indicated at 20 in Figure 1, which includes the applicants governing mechanism as shown in Figure 2. A pump 22 supplies fuel under pressure to fuel control 20 through a conduit 24, a portion of which fuel may be by-passed back to the pump inlet through a conduit 26.

The fuel control 20 contains mechanism adapted to respond to compressor inlet temperature (T,,), as sensed by a temperature bulb 28, compressor inlet pressure (P,,), picked upby a pitot tube 30, compressor discharge pressure (P picked up at a second pitot tube 32, engine speed (N), which is transmitted to said control by means of a bevel gearing arrangement 34 and 36 and a governor drive shaft 38, and to the position of a pilots control lever 40, which is connected to the fuel control device by means of a link 42, a lever 44 and a shaft 46.

The control lever 40 is mounted on a rotatable shaft 48 in a control quadrant 50 and is manually actuable to select any desired operating speed for the engine by means of the link and lever 42 and 44 and other mechanism to be described, and to initiate the injection of a secondary liquid to the inlet section of the compressor 13 by means of a link, lever and shaft 52, 54 and 56, respectively, which are positionally controlled by a cam 58 mounted on shaft 48 for controlling valvular means, not shown, in a liquid flow regulator 60. An inlet conduit 62 conducts a liquid from a pump 63 to the regulator 60 whenever injection thereof is initiated, said regulator discharging the liquid to the inlet section of the compressor through a discharge conduit 64, a manifold 66, and a plurality of nozzles 68. Whenever the pilot actuates lever 40 to a full forward position, to initiate the injection of the secondary liquid, hereinafter called water, to the inletof the compressor, a pair of bar contacts 70 and 72 close an electrical circuit through the 4 application of Harry C. Zeisloft, Serial No. 248,402,

supra, to which the Pitot tube 32 is connected by way of pilots lever 40, a lead 74, a solenoid valve 76 mounted I on fuel control 20, and a ground 78, which action results in effectively resetting the governing mechanism throughout the period of time that water is injected at the compressor in a manner and for a purpose to be later described.

Referring now to Figure 2, the governing mechanism is shown contained within a housing 80 of the fuel control device 20, which receives, fuel at a pressure P from condult 24 in an inlet passage 82 and an annular chamber 84 formed between the housing and a fixed cylindrical sleeve member 86, and which discharges fuel to the times controlled as a function of compressor discharge pressure by a geared rack member 104 and a gear sector 106 fixed on anextension 108 of valve 90 and'having splined gear teeth 110 in mesh with the gear teeth of rack 104. The geared rack 104 is movable in a plane which is vertical to the drawing, and is positionally controlled as a function of compressor. discharge pressure by mechanism such as is disclosed in the copending conduit 112, said rack and the sector 106 cooperating to maintain a given angular position of valve for each value of compressor discharge pressure.

The axial position of metering valve 90 within sleeve 86 is controlled either by a contoured three-dimensional acceleration cam 114, which is adapted to cooperate with a cam follower and valve rod 116 and 118 during an acceleration of the engine, or by all-speed governing mechanism contained within housing chamber 120 and connected to the metering valve by a power servo piston 122 and a walking beam 124. The walking beam 124 is adapted to be variously fulcrumed at a ball joint connection 126 on a servo piston rod 128, at a pivot connection 130 to a rod 132 of a water injection governor reset piston 134, or at a ball joint connection 136 on the cam follower rod 118 in a manner to be described. The axial position of valve 90 is at all times determined by that mechanism which demands the least quantity of fuel, i. e. the acceleration cam and the governing mechanism are arranged in mutually overriding relation, as hereinafter described, so that that one which tends to fix the smallest area at metering ports 88, 92 controls.

The acceleration cam 114 is mounted on a shaft 138 which is rotatably and axially actuable as a function of certain engine operating parameters such as, engine speed and compressor inlet temperature. The shaft 138 carries a pinion 139 fixedly secured thereto, said pinion being. engaged with and rotated by a rack 141 formed on a rod fixedly secured to a piston 143. The piston 143 is responsive to a servo pressure P, which is controlled by a half-ball servo valve 145. The half-ball servo valve 145 is positioned as a function of engine speed by a pivot lever 147 operatively connected between said half-ball servo valve and the centrifugal weights 160. The shaft 138 is positioned axially by a bellows 149 which has an operative connection with the temperature bulb 28 by means of atube 151, the bellows and tube being filled with suitable fluid or naturally responsive to temperature changes registered by the bulb 28. The structural details and. mode of operation of the above-mentioned mechanism for rotatably and axially actuating the shaft 138 is conventional and will be easily understood by those skilled. in the art. The acceleration fuel flow schedule may be controlled by the cam to vary as a predetermined function of P,,, T,, and N, such that maximum allowable turbine inlet temperature is substantially maintained throughout a predetermined portion of the acceleration'schedule, and the phenomenon known as compressor surge or stall is not encountered. The angular and axial position controls for valve 90 at all times cooperate to define a metering area formed at the portion of registry between ports 88 and 92. For example, as compressor discharge pressure increases, rack 104 actuates gear sector 106 to move valve 90 in a clockwise direction, as viewed from the top thereof, increasing dimension ;c of the metering port in proportion to the increase in said pressure, and variation in any engine operating parameter which effects a change in the axial position of metering valve 90 varies dimension y of port 140.

Preferably, 'a constant fuel pressure differential is at all times maintained across metering port 140 by a regulator valve means generally shown at 153 and preferably of the type disclosed in U.S. Patent No. 2,689,606, granted'September 21, 1954, to Frank C. Mock and assigned to the present assignee whereby the fiow through said port is always a predetermined function of only those engine operating parameters which control the angular and axial positions of valve 90.

The governor mechanism contained within chamber 120 connects the pilot controlled levers 40 and 44 to the power servo piston 122 by Way of the shaft 46, a governor setting cam 142 mounted on shaft 46 for rotation agate-ms governor'spring 146 mounted" between spring retainers "which abut the'rod 1'44"and "a"s'ervo valve-lever- 148,

fulcrum'edat 150, ahalf-balttypeservo'valve 152 connected to the lever'148 and cooperating with a discharge jorifice 154 in a servopressure 'passa'ge' 156; a governor "feedback tension spring "'158resilie"ntly connectingthe "servo piston rod'128with theleftend of 'servo lever 148, and apair of rotatable centrifugalweights 160 mounted on brackets 162' at pivots 164=for rotation'witlr amountting plate 166 which is keyed'tothe 'go'vernordriveshaft 38, said centrifugal Weightshaving foot members 168 in "abutment with a flange 170 "of a force transmitting 'rod' 172, which in turn abuts a lever 174 pivoted at 176 ifortra'nsmitting'a moment of the'force output of weights 160 to servo lever 148'at a"'governor slope' adjusting nut 178. The compressor inlet pressure"responsivemechanism may take the form of an evacuated bellows 179 "suitably mounted in a "sealed chamber '181" which receives compressor inlet air pressure from pitot tube 30 via a conduit 183 A rod "185 -extendsfrorn themovable end' of bellows 179'into'fengagement'with the shaft 46, "such'that a given'axiahposi-tion of the ca1n142'ismaintained for each value ofthe"cornpressorinlet' pressure ""P,,.' The bellows 179 may be replaced "by temperature "sensing mechanism similar'to the aforementioned'temperature sensing bulb 28, tube 151' and bellows 149'in "which case theshaft '46 could be actuated as a'function of compressor inlet temperature T The compressor inlet pressure responsive 'mechanismmay be combined to form conventional density sensitiveiapparatus, not

'tive with'the gear sectorf'106: which is formed on an "extension 108 of the fuel metering valve member 90. and which has splinedgearteethtllO in mesh withithe gear shown, such that the'sh'aft 46"is"positioned'as a function g of compressor inlet pressure and" temperature.

The servo pressure (P passage 156c'onn'ects"the P 'pr'essure'chamber 84' to chamber 120, which" is connected "to pump'by-pass' 'conduit'26'iby a passage, notshown, at *purnp inlet pressure P Adisch'argepressureregulator valve 180'in passage 1'56 is-adapted'tdma-int'ain a' constant pressure in said passage upstream jota calibrated restricf't-ion'182, thepressure P beneathpower piston 122 there- "-'fore varying solely as a function of the area ratio be- "tweenjrestriction 182 and orifice 154. A' power'return .spring184 and fuel at pump inlet pressure in achamber 186 oppose P pressure and spring158 across piston 122.

A"servo balance spring 188, adjustable by means of a :screw'190, is utilized to act on levery148 at 192 for the (purpose of compensating for variationsinrnanufacturing tolerances between the designed rates of'springs'146 and 1'58, and for insuring that said latter springs will sustain za pre-load even whenthe engine isat rest; this latter'function' insures that neithersp'ring 146 nor15 8w-illever be extended to a free height or no-load condition. If either of said springs were everto reach a no-load condition they might become disconnected frorntheirrespective retaining'means. The effective force outputof the balance spri'ng188on'theservo system remains substantially ciohs'tantfirrespective of variations in engine 'operating conditions, asthe result'of an arrangement'which effects a total range of movement ofservo valve 152 amounting to only a few thousandths of an inch.

During all conditions of engine governing and ,equilib rium operation,except during a period ofwaterinjection, the fulcrum 130 of walking beam :1 24.is maintained in the position shown by opposed spring loaded pistons -;134-- and 194, which are reciprocable within a cylinder 196; and which are urged in'opposite directions by springs 5-198-and 200 in chambers'202 and--204,'respectively. A chamber 206, formed b'etween said pistons," is'normally connected to pump inlet pressure P in housing chamber 120 by way of a restriction'208,a passage 210, chamber 204; and ap'air ofbleeds'-212-inthe piston1'194. The

' elian'ibei" 2'02- isvented to pump inlet pressure 1 through a "90 through rack 104 and sector 106 such that. a given angular position, of v'alve'90 is maintained forcaoh 4 by way of the restriction208,.the passage 210, the chamber204, and the bleeds 212 in the piston 194. The angular stop member 216 normally fixed the position of the housing' aperture214. Thefpdsition 'oii piston E4 normally fixed by an annular stop mernber 2-16.

The solenoid valve 76.1cornprises a valve member 218, which is normally. held in a closedposition in a water .conducting 'conduit22 0 bya spring'222, and a suitably wound coilt224 connected tothe'-ground78 and toftheelecjtrical bar contact "72 by lead 74, .said coil being energizable "to actuate valve 218; against 'spring'22 2 and permit water tolenter a chamber. 226' by Way of. a conduit. 22 0,

which may be connected to. the.co nduit62."'The chamher 26 connects with the'drain conduit22 8 through a port 230, and is formed on one side ofadiaphragm" 232 .to which is connected adouble;acting valve5234, said valve being adapted to allow' connection between all; fuel pressure conduit 236 andthe "ch'arnber204duringxa period of water injection. following demand therefor byj'the pilot. A demand for' water injection causes energization .ofsolenoid valve 76. and a'ditferential pressure across "diaphragm 232 in an upward direction, which results in closing port'230, andfopening conduit 236 to chamber 132 abuts an. adjustable waterinjection stop 242, thereby teeth of rack memberf104. Therack "104is formed. on

t a rod 105 whichis. fixedly secured to the movableend of an'evacuated bellows 107. "The bellows 107 is ,mounted in a'se al'e d chambef109 which receives comjpressor dischargefpressureP5 ir'om Pitot tube"32 via conduit 112. Thebello ws'107 responds to the. compressor discharge pressureP in"charnber 1.09 an'd rotates valve valve of compressor discharge .pressure P In Figure 5 there is a schematic showing of a modification "of a portion of the apparatus shown inFigur'e 1. The'water injection governor reset piston 134 is shown connected through the rodf132 to 'the walking beam 124 at a pivot connection 130. Also the ball joint connection 126 of'the walking beam 124.is sh own; The spring 198 Withinchambe'r'202 is shown urging the resetfpiston 134 in an opposite direction within the cylinderI196 relative to the piston'194 which is rged ,by the jsp'ring 200 within the chamber'204. (The chamber 206:form'ed between thepistons 134 and 194' is normally connected to pump inlet pressure P in the housing chamber-1.20

piston/194. The double acting valve member 234, described as connected between the conduit 236 "mid -the chamber204 and responsive. to water injection, is shown.

I In accordance with the modification as shownin :Figure 5 a control'bleed'262 is provided to vent the chamber 202 to thehousing chamber'120a'nd a control valve including a movable valve member264 is connected between conduit 236' containinghigh pressure'fuel and the chamber 202 at the top side 'ofrthe reset piston "'134. IThG "valve member'264 is controlled in position by a pressure drop 'responsive diaphragm 266,. which is responsive to the pressure within the "tailpipeof engi ne 10 behind the turbine -14as ventedto the chamber 268" and is responsive pressure drop necessary before 'thehighmressure fuel 7 from the conduit 236 is vented to chamber 202 and the top side of the reset piston 134.

Operation Referring now to Figure 3, sea level acceleration, governing, and steady state engine characteristics are qualitatively illustrated by the curves244, 246 and 248 and 250, respectively, on the curve chart which is plotted on the coordinates of fuel flow in pounds per hour versus engine speed in r.p.m. The basic contour of the characteristic sea level acceleration curve 244 is fixed by the contour of the acceleration cam 114, which is actuable as a function of certain engine operating parameters, as hereinbefore described, whereas the height or level of said curve above the engine speed coordinate is primarily controlled by the compressor discharge pressure responsive mechanism. The governor fuel cut-off curve 246 illustrates the operation of the force servo type proportional governor from the acceleration curve to a selected speed point on an engine steady state operating curve. The steady state curve 248 illustrates engine fuel flow demand at any given engine speed during sea level operation wtihout water injection at the compressor inlet, whereas the curve 250 illustrates such engine demand with water injection.

Assume that the engine has been started and accelerated to the steady state operating point a in the midspeed range. In this condition of operation the pilots control lever 40 will be positioned approximately midway between the ends of quadrant 50, in which position solenoid valve 76 is de-energized and the pump inlet pressure in chamber 238 maintains double acting valve 234 in the position shown so that the position of fulcrum 130 is fixed, as shown. The contour of the Water regulator control cam 58 is such that no movement is imparted to link and lever 52 and 54 during actuation of lever 40 to the mid-position, and no injection occurs at nozzles 68; with lever 40 in the mid-position link and lever 42 and 44 position the governor setting cam 142 on shaft 46 so as to impose a speed selecting load on governor spring 146 through cam follower rod 144 which demands that engine operating speed existent at point a. In this condition of operation the half-ball servo valve 152, being maintained in fixed position by an existent force balance on lever 148, controls a servo pressure P in passage 156 which imposes a force on servo piston 122; this force is balanced by the opposing forces of the governor feedback spring 158, the power return spring 184, and the pump inlet pressure in chamber 186, whereby the position of walking beam 124 is fixed thereby controlling the axial position of metering valve 90 such that the area of metering port 140 controls that quantity of fuel flow to the nozzle 16 which is necessary to maintain engine speed as set at point a.

The forces, acting on servo lever 148 in a direction which tends to move servo valve 152 in an opening direc tion, i.e. in a direction which would result in an accelerating fuel flow to the engine, consist of the moment forces of governor spring 146, feedback spring 158, and the fuel pressure force on servo valve 152 at orifice 154, all acting about fulcrum 150. These moment forces are opposed and balanced by the moment force of the centrifugal weights 160, which varies as the square of engine speed, and the substantially constant moment force of the servo balance spring 188. At any given speed, the engine driven centrifugal weights 160 generate an effective force output on lever 148 which is equal to the weight force output times the ratio of the lever arm between rod172 and fulcrum 176 to the lever arm between nut 178 and fulcrum 176. The force output of weights 160 is therefore diminished at lever 148 by the lever ratio factor, said factor being adjustable by nut 178 to adjust the governor cut-off slope, as will be hereinafter described.

Assume now that the pilot actuates control lever 40 in a counterclockwise direction to select, say, a maximum operating speed for the engine, as denoted by point d on curve 248, and as illustrated by the position of lever 40 in Figure 1. As the pilot rotates lever 40 to the indicated maximum speed position, the fuel control unit reacts substantially instantaneously as follows: Governor setting cam 142 is rotated on shaft 46 to a position at which the cam rise imposes maximum compression on governor spring 146 to select that speed at which the governor weight force and other forces acting on servo lever 148 will be in equilibrium, as illustrated at point d; servo lever 148, being no longer in balance, rotates a very slight amount in a clockwise direction to increase the area ratio between orifice 154 and restriction 182, thereby instantaneously decreasing servo pressure P, and unbalancing the forces across servo piston 122; and the force unbalance across piston 122 actuates the piston downwardly and the walking beam 124 about fulcrum in a clockwise direction until cam follower 116 comes into contact with acceleration cam 114, in which position the metering area has increased to effect an increase in fuel flow from point a on curve 248 to point b on curve 244. The amount of compression imparted to governor spring 146 which is in excess of that necessary to effect an acceleration to point g on curve 248 results in a continued downward movement of piston 122, following contact of cam follower 116 with acceleration cam 114, about a new fulcrum 136, as pivot 130 and piston 134 actuate piston 194 downwardly against spring 290 until piston 122 reaches a position in which the decreased loadings on springs 184 and 158 plus the low pressure in chamber 186 again balances the force of pressure P the loading force imposed on the acceleration cam through follower 116 is thereby held to a relatively small amount, which results only from the degree of compression imparted to the light spring 200.

The increase of fuel flow from point a to point b results in an excess over that required to run the engine at the existing speed, and acceleration proceeds along curve 244, as determined by the contour of cam 114 which effects an opening movement of metering valve 90 in an axial direction; at the same time compressor discharge pressure responsive rack 104 effects an opening rotational movement of valve 90. The combined axial and rotational movement of valve 90 results in a fuel flow versus speed characteristic such as is illustrated by the curve segment be. As acceleration of the engine proceeds from point b, and the rate of opening movement of valve 90 is determined by the rotating cam 114, it is apparent that the fulcrum of walking beam 124 will shift from pivot 136 to pivot 126, as spring 260 actuates pistons 194 and 134 upwardly until piston 194 again abuts stop,216 and pivot 130 is returned to the position shown. Contact between follower 116 and the decreasing rise of cam 114 is thereby maintained while the engine is accelerating.

At the speed indicated at point e, the centrifugal weights have generated a force output which is sufficient to begin to overcome the force moments of governor spring 146 and feedback spring 158, said spring 158 being, at this time, in a relatively relaxed condition. Servo valve 152 therefore moves slightly upwardly to reduce the area ratio between orifice 154 and restriction 182, thereby producing an immediate increase in pressure P which unbalances servo piston 122 in an upward direction, resulting in a counterclockwise rotation of walking beam 124 about fulcrum 130 and a movement of follower 116 away from acceleration cam 114 to reduce the dimension y of metering port 140. As piston 122 moves upwardly, feedback spring 158 elongates and produces an increasing moment of force on servo lever 148 in the same direction as that produced by governor spring 146. This action results in continued acceleration of the engine as fuel flow decreases along the governor break curve 246, inasmuch as the increasing force outthe diaphragm 266 and valve member 264 which in response to a predetermined pressure drop are biassed upward whereupon the valve member 264 prevents the flow of high pressure fuel from conduit 236 to chamber 202. If afterburner flame-out should occur, the pressure in chamber 202 would drop and allow the spring 272 to bias the diaphragm 266 and valve member 264 downward whereupon high pressure fuel would be allowed to flow from conduit 236 to chamber 202. The piston 134 would move downwardly against stop 216 in response to the pressurization of chamber 202 and effect counterclockwise movement of walking beam 124 about the pivot 126 which, in turn, causes movement of metering valve 90 in a closing direction and a corresponding decrease in engine fuel flow. The controlled reduction in fuel flow effectively maintains engine speed at a safe value until the tailgate can be closed and tailpipe Ipressure again increased, at which time the diaphragm 266 would actuate valve member 264 to a closed position to thereby disestablish communication between conduit 236 and chamber 202. The piston 134, fulcrum 130, and metering valve 90 would then return to the positions shown to maintain the selected speed.

It will be apparent to those skilled in the art that various changes in the structure and relative arrangement of parts may be made without departing from the scope of my invention.

I claim:

1. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, valve means for controlling the fuel flow through said conduit, engine speed responsive means operatively connected to said valve means for controlling the flow of fuel therethrough as an inverse function of engine speed, said operative connection including lever means having a fulcrum maintained in a normally fixed position during equilibrium operation of the engine, means for conducting an engine thrust augmenting fluid to the compressor, and means operatively connected to said fulcrum for varying the position thereof whenever injection of said fluid is initiated.

2. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, first control means for conducting a thrust augmenting fluid to the compressor, second control means for initiating the flow of said fluid to the compressor, engine speed governor means for controlling the flow of fuel through said-conduit, and third control means operatively connected to said governor means and responsive to the conduction of fluid to the compressor by said first control means for shifting the governor fuel cut-off characteristic following a demand for the injection of said fluid to the compressor.

. 3. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, means for conducting an engine thrust augmenting fluid to the compressor, governor valve means for controlling the flow of fuel through said conduit, engine speed responsive means operatively connected to said valve means for controlling the flow regulating position thereof at a selected speed of engine operation, said operative connection including lever means and a fulcrum for said lever means movable from a first to a second operating position whenever said thrust augmenting fluid is conducted to the compressor, and fluid pressure responsive means adapted to actuate said fulcrum from said first to said second operating positions for maintaining the selected engine speed during injection of said thrust augmenting fluid.

'4. An engine speed governor comprising governor valve means for controlling the flow of motive fluid to the engine, an engine speed responsive governor mechanism operatively connected to said valve means for controlling the flow regulating position of said valve means as an inver e function of engine speed to operate aid engine in accordance with a first steady state operating characteristic, first control means operatively connected to said engine for shifting the engine operation to a second steady state operating characteristic, second control means operatively connected to said governor mechanism for selecting an operating speed for the engine, with said latter operative connection including third control means for effectively resetting said governor mechanism to maintain the selected speed following a shift from the first to the second steady state operating characteristic of the engine.

5. An engine speed governor comprising governor valve means for controlling the flow of motive fluid to the engine, an engine speed responsive governor mechanism operatively connected to said valve means for controlling the flow regulating position of said valve means as an inverse function of engine speed to operate said engine in accordance with a first steady state operating characteristic, first control means operatively connected to said engine for shifting the engine operation to a second steady state operating characteristic, second control means operatively connected to said governor mechanism for selecting an operating speed for the engine including a fluid pressure responsive valvular means for effectively resetting said governor mechanism to maintain the selected speed following a shift from the first to the second steady state operating characteristic of the engine, and third con trol means responsive to actuation of said valvular means for varying the flow regulating position of said valve means at the preselected engine speed.

6. An engine speed governor comprising valve means for controlling the flow of motive fluid to the engine, an engine speed responsive mechanism operatively connected to said valve means for governing fuel flow to maintain any given selected engine speed, and control means connected to said speed responsive mechanism for selecting an operating speed for the engine, said operative connection including a walking beam, a first pivot means connecting said valve means to said beam, 21 second pivot means connecting fluid pressure responsive means to said beam and a third pivot means connecting said engine speed responsive means to said beam, said second pivot means having a first operating position and a second operating position, with said second pivot means being in said first position during control of said valve means by said engine speed responsive means, and with said fluid pressure responsive means being operative to actuate said second pivot to said second position in response to said speed selecting control means being moved to a. predetermined control position.

7. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, means for conducting an engine thrust augmenting fluid to the compressor, valve means for controlling the flow of fuel through said conduit, engine speed responsive mechanism for controlling the flow regulating position of said valve means as an inverse function of engine speed, means connected to said speed responsive mechanism for selecting an operating speed for the engine, an operative connection between said speed responsive means and said valve means including means adapted to actuate said valve means in an opening direction at a given selected engine speed during injection of said thrust augmenting fluid, and means for coordinating the actuation of said valve means by said latter means with said thrust augmenting fluid conducting means.

8. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, means for conducting engine thrust augmenting fluid to the compressor,

valve means for regulating the flow of fuel through said conduit, engine speed responsive mechanism operatively connected to said valve means for varying the flow regu lating position thereof as an inverse function of engine speed, and means connected to said engine speed responsive means for selecting an operating speed for the engine, said operative connection including a lever, a lever fulcrum maintained in a normally fixed first position during control of said valve means by said engine speed responsive means, means permitting actuation of said fulcrum to a second position following initiation of an acceleration of the engine by said speed selecting means and means for actuating said fulcrum to a third position following initiation of flow of said thrust augmenting fluid at a given selected speed of engine operation.

9. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, a fuel conduit for conducting fuel to the burner, first control means for conducting an engine thrust augmenting fluid to the compressor, valve means for regulating the flow of fuel through said conduit, an engine speed governor mechanism operatively connected to said valve means for controlling the flow regulating position thereof, second control means connected to said governor means for selecting any given desired operating speed for the engine, said operative connection between said governor mechanism and said valve means including a control member having a first pivot connection with said valve means, means operatively connected to said control member and said second control means including a second pivot connection, means operatively connected to said control member and said first control means including a third pivot connection, said control member being pivotally controlled about said third pivot connection during governor cut-ofi and equilibrium operation of the engine at any selected speed, said control member being pivotally controlled about said first pivot connection subsequent to a request for an acceleration of said engine by said second control means, and said control member being pivotally controlled about said second pivot connection subsequent to initiating a flow of said thrust augmenting fluid.

10. In a fuel feed and power control system for a gas turbine engine having a burner and a compressor, first control means for controlling the flow of a first fluid to the burner, second control means for controlling the flow of a second fluid to the compressor, and third control means operatively connected to said first means and to said second means for varying the flow of said first fluid following initiation of the flow of said second fluid by said second control means.

References Cited in the file of this patent UNITED STATES PATENTS 1,188,197 Norton June 20, 1916 2,675,220 Feilden Apr. 13, 1954 FOREIGN PATENTS 521,255 France Mar. 3, 1921 929,159 France June 30, 1947 

